Stereoselective synthesis and ROESY 1H NMR study of bidiaziridines

The bisaziridination reaction of symmetric (E-s-trans-E)-α-diimines using ethyl nosyloxycarbamate as aminating agent yields symmetrically functionalized bidiaziridines, under mild conditions. The reactions take place with very high stereoselectivity giving only bidiaziridines with total retention of the starting α-diimine configuration, as determined by NMR measurements. Moreover, only a single pure diastereomer, derived from attack of the aza-anion on the opposite faces of conjugate system was obtained, starting from chiral substrates. ROESY analyses clearly show that all nitrogens have a stable pyramidal conformation, and the absolute configurations of new chiral centers were assigned. © 2012 American Chemical Society.